Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 02-09-2018, 12:37 PM   #1
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 1,203
Default Replacement Ignition Coil

The replacement ignition coil sold by Model A parts suppliers is a Standard Motor Products UC14T.
http://ecatalog.smpcorp.com/STD/#/ve...m/UC14T?type=s
Does anyone have the output voltage spec for this coil?
__________________
Bob Bidonde

Last edited by Bob Bidonde; 02-09-2018 at 01:03 PM.
Bob Bidonde is offline   Reply With Quote
Old 02-09-2018, 02:17 PM   #2
3.6rs
Senior Member
 
3.6rs's Avatar
 
Join Date: Jul 2010
Location: Belgistan (formerly known as Belgium)
Posts: 561
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Bob Bidonde View Post
...
Does anyone have the output voltage spec for this coil?
Why would this be important ?
3.6rs is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-09-2018, 02:34 PM   #3
Bob-A
Senior Member
 
Bob-A's Avatar
 
Join Date: May 2010
Location: Central FL, USA
Posts: 917
Smile Re: Replacement Ignition Coil

Go with the Pertronix Flamethrower coil! You will be glad you did......

Bob-A
Bob-A is offline   Reply With Quote
Old 02-09-2018, 02:44 PM   #4
AL in NY
Senior Member
 
AL in NY's Avatar
 
Join Date: May 2010
Location: Southern Upstate New York
Posts: 786
Default Re: Replacement Ignition Coil

I agree with Bob-A, but be sure to order the epoxy filled coil.

Epoxy 1.5 ohm black coil = PN 40111
Epoxy 3.0 ohm black coil = PN 40611
__________________
AL in NY
AL in NY is offline   Reply With Quote
Old 02-09-2018, 03:26 PM   #5
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 1,203
Default Re: Replacement Ignition Coil

6V System
High-voltage output numbers are inconsistent on this forum. I seek the best 6V replacement coil which has the highest output voltage (highest turns ratio).

12V System
40611 Pertronix coils made in China have been recalled because they fail under load. There is another 40611 made in Mexico. There is also a report that some boxes have the wrong part number. What you actually get in the box is a mystery.

I bought a Bosch 00012 and it runs really well.
__________________
Bob Bidonde

Last edited by Bob Bidonde; 02-09-2018 at 03:51 PM.
Bob Bidonde is offline   Reply With Quote
Old 02-09-2018, 03:46 PM   #6
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

I'm with Bob-A and AL in NY . I use the epoxy filled 3 ohm black coil= PN 40611 on my 12 volt roadster . These coils need no resister . Like Bob-A says you'll be glad you did . I get instant starts and improved power that you can feel . Better spark burns the gas better and gets more power from it. The first thing i did after installation was idel down the carbs.The engine ran so much better , it actually picked up quite a few RPMs .The coil is a 40.000 volt performance part but looks like any normal replacement coil . They even have a chrome version if you would like .

Last edited by Purdy Swoft; 02-09-2018 at 03:53 PM.
Purdy Swoft is offline   Reply With Quote
Old 02-09-2018, 04:11 PM   #7
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

Sorry Bob Bidonde, That hasn't been my experience With the Flame thrower coil .Do you actually have any experience at all with the 40611 coil . It wouldn't matter to me where it was made if it is good . Mine have all been made in Mexico . The 40611 coil that I installed on my roadster has performed flawlessly for the past 12 years . If you can't use it don't try it .

Last edited by Purdy Swoft; 02-09-2018 at 04:19 PM. Reason: added the name Bidonde .
Purdy Swoft is offline   Reply With Quote
Old 02-09-2018, 11:36 PM   #8
Smog Tech
Senior Member
 
Smog Tech's Avatar
 
Join Date: Jan 2014
Location: Arcadia, CA
Posts: 123
Default Re: Replacement Ignition Coil

I use an oil filled 1.5 Ω Pertronix Coil in my 6v Town Sedan. I do mount the coil with the high voltage terminal pointing up.
Smog Tech is offline   Reply With Quote
Old 02-10-2018, 01:23 AM   #9
1930marie
Senior Member
 
1930marie's Avatar
 
Join Date: Sep 2015
Location: Oregon
Posts: 238
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Smog Tech View Post
I use an oil filled 1.5 Ω Pertronix Coil in my 6v Town Sedan. I do mount the coil with the high voltage terminal pointing up.
Does this coil have a stock A look and where can I buy one like you installed? Thanks!
__________________
They know enough who know to learn.
1930marie is offline   Reply With Quote
Old 02-10-2018, 09:27 AM   #10
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 1,203
Default Re: Replacement Ignition Coil

Hi Purdy! Yes, I have a 40611 Flame Thrower, but it failed so I replaced it with a Bosch 00012 (Blue Coil).
Attached Images
File Type: jpg DSCN2394.jpg (53.4 KB, 91 views)
__________________
Bob Bidonde
Bob Bidonde is offline   Reply With Quote
Old 02-10-2018, 10:35 AM   #11
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 1,401
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Bob Bidonde View Post
The replacement ignition coil sold by Model A parts suppliers is a Standard Motor Products UC14T.
http://ecatalog.smpcorp.com/STD/#/ve...m/UC14T?type=s
Does anyone have the output voltage spec for this coil?
Contact Standard Motor Products they should have it.
__________________
Talk slow, think fast.
katy is offline   Reply With Quote
Old 02-10-2018, 10:50 AM   #12
BUBBAS IGNITION
Senior Member
 
BUBBAS IGNITION's Avatar
 
Join Date: May 2010
Location: SPEEDWAY INDIANA
Posts: 3,503
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Bob Bidonde View Post
Hi Purdy! Yes, I have a 40611 Flame Thrower, but it failed so I replaced it with a Bosch 00012 (Blue Coil).
You guys need to read this post on the V8 forum........
www.fordbarn.com/forum/showthread.php?t=238737
__________________
If it Makes Spark, we do it !!!!
www.bubbasignition.com
jimlinder@juno.com
BUBBAS IGNITION is offline   Reply With Quote
Old 02-10-2018, 11:46 AM   #13
jhowes
Senior Member
 
Join Date: Jul 2010
Posts: 577
Default Re: Replacement Ignition Coil

A lot of "thanks for the heads up" on the v8 forum but not much in the voltage (6v) or the output. Is it 40,000 or what? I would like to know if they are reliable, is the voltage for our 6v cars, and is the output 40,000 or so? Where do you buy them? I am guessing that the 1.5 ohm is for our 6v systems.
jhowes is offline   Reply With Quote
Old 02-10-2018, 11:53 AM   #14
duke36
Senior Member
 
Join Date: Jun 2015
Posts: 835
Default Re: Replacement Ignition Coil

Bob: we use Bosch like yours though turned terminals up as in post 8 for oil filled. We have an older tar filled (or whatever medium) 3ohm Bosch (German made) that works well also. The newer ones are supposedly made in Brazil. The oil filled coil we tried gets hot to the touch.
duke36 is offline   Reply With Quote
Old 02-10-2018, 12:56 PM   #15
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

Some have claimed that the epoxy filled flame thrower coils get too hot to touch . I have had no such problem with mine . I could use either the epoxy or oil filled version as long as they are mounted correctly. A high voltage performance coil will no doubt get warmer than a low voltage coil but not that hot . The epoxy version was recommended so I use it . No problems in 12 years .I can grab and hold mine with no discomfort . If others are having problems with the flamethrewer coil , there is no telling what their problem may be . A lot of people use them with results the same as mine .
Purdy Swoft is offline   Reply With Quote
Old 02-10-2018, 04:18 PM   #16
duke36
Senior Member
 
Join Date: Jun 2015
Posts: 835
Default Re: Replacement Ignition Coil

Our 12 volt new oil filled gets quite hot but not so much that one can't grasp it. It is cooler than the distributor housing on a warmed engine for reference. The STD UCT coils are made in China. We have also a new UCT15 with internal resistor that measures 4.4 ohms across the primary and 8100 at the secondary.
duke36 is offline   Reply With Quote
Old 02-10-2018, 05:14 PM   #17
BILL WILLIAMSON
Senior Member
 
BILL WILLIAMSON's Avatar
 
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,408
Default Re: Replacement Ignition Coil

Smog Tech,
Where'd you get the OHM symbol in your post?----Or is it a COIL BRACKET?
The Dog & I can't find one on our CHEAP Keyboard
Bill W. & Buster T.
__________________
"THE ASSISTANT GURU OF STUFF"
BILL WILLIAMSON is offline   Reply With Quote
Old 02-10-2018, 06:56 PM   #18
Smog Tech
Senior Member
 
Smog Tech's Avatar
 
Join Date: Jan 2014
Location: Arcadia, CA
Posts: 123
Default Re: Replacement Ignition Coil

Bill,
On a MAC the Ω is option z.
Smog Tech is offline   Reply With Quote
Old 02-11-2018, 12:12 AM   #19
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Bob Bidonde View Post
The replacement ignition coil sold by Model A parts suppliers is a Standard Motor Products UC14T.
http://ecatalog.smpcorp.com/STD/#/ve...m/UC14T?type=s
Does anyone have the output voltage spec for this coil?
Answer: It depends!......Depends on how much voltage is needed to jump the plug gap. If only 5,000 volts will fire the plug, that is all the coil will put out. Even if you have a double super whammy "40,000 volt" coil it will still only build up secondary voltage to the point where the spark is strong enough to jump the plug gap, which will never reach 40,000 volts on a Model A, or any stock engine (unless you have totally burned out plug electrodes or open wires, etc.). An ultra high compression or supercharged engine running at wide open throttle may need this much voltage capability, though.
To test coil output, try a "Lisle #20700 Spark Tester". Or, go to a shop with a scope, hook it up and pull a plug wire off and watch the screen.
40 Deluxe is offline   Reply With Quote
Old 02-11-2018, 06:41 AM   #20
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 26,981
Default Re: Replacement Ignition Coil

I'm not sure if my original coil is reliable, as I'm still testing it. It's only been in use for 90 years.
Attached Images
File Type: jpg Terminal Box and Cleaned Paint.jpg (66.9 KB, 63 views)
Tom Wesenberg is online now   Reply With Quote
Old 02-11-2018, 09:06 AM   #21
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 1,203
Default Re: Replacement Ignition Coil

Tom,
After 90 years of service, what do you think the remaining life is? I hope you have a spare coil if you tour out of town in your Model A.
__________________
Bob Bidonde
Bob Bidonde is offline   Reply With Quote
Old 02-11-2018, 11:57 AM   #22
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

About the only thing that effects original tar filled model A coils is carbon tracks that extend up to the metal tube housing. Carbon tracks can short the coil but can be scraped off . Carbon tracks are mentioned in the service bulletins . Like Tom , Ive never had a problem with an original , even if it was beat up and rusty .

Last edited by Purdy Swoft; 02-11-2018 at 12:05 PM. Reason: added the letter w
Purdy Swoft is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-11-2018, 12:36 PM   #23
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by 40 Deluxe View Post
Answer: It depends!......Depends on how much voltage is needed to jump the plug gap. If only 5,000 volts will fire the plug, that is all the coil will put out. Even if you have a double super whammy "40,000 volt" coil it will still only build up secondary voltage to the point where the spark is strong enough to jump the plug gap, which will never reach 40,000 volts on a Model A, or any stock engine (unless you have totally burned out plug electrodes or open wires, etc.). An ultra high compression or supercharged engine running at wide open throttle may need this much voltage capability, though.
To test coil output, try a "Lisle #20700 Spark Tester". Or, go to a shop with a scope, hook it up and pull a plug wire off and watch the screen.
If this was really the case, no matter what coil or distributor that was used would increase the spark . This is really no so !!! I use a gap of .035 - thats thirty five thousants at the spark plugs . Running at idle speed is not an extra strain on the coil . Idle speed doesn't require extra voltage to jump the .035 gap at the spark plugs. If my Flame thrower coil doesn't increase the spark . Why would the idle rpm increase to the point that I had to readjust the idle speed . I have had similiar results with other performance coils like the 30.000 volt bee hive coils . These coils give performance that a person that has actually used one can't deny .
Purdy Swoft is offline   Reply With Quote
Old 02-11-2018, 02:07 PM   #24
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Bob Bidonde View Post
Hi Purdy! Yes, I have a 40611 Flame Thrower, but it failed so I replaced it with a Bosch 00012 (Blue Coil).

I usually look at this forum several times a day . I haven't seen any inconsistant voltage ratings of the Flamethrower type coil that I use posted on this forum . I do remember a post where Mr HL Chauvin posted what one of the Pertronix engineers told him . There was no mention of a voltage difference between the 1.5 ohm and the 3.0 ohm versions of the flamethrower coils . The engineer hinted around that the 12 volt 3.0 version could be the better choice for performance . You question the voltage out put of the Flamethrower coil . What is the advertised voltage of the Bosch 00012 coil ??? If Flamethrower coils have been recalled, WHY hasn't my coil been recalled ? You mention and post a picture of the Bosch 00012 coil , mounted on your car . Post number 14 states that he uses a blue oil filled Bosch coil like yours . If your Bosch coil is oil filled you have yours mounted upside down . Oil filled coils that are mounted wrong usually fail early , no matter what brand that they are . If you used the lower priced oil filled Flame thrower coil and mounted it wrong, that could be the reason that it failed . The solid epoxy coil can be mounted as original , not necessarily so with the oil filled version .

I use the 40611 epoxy coil . Mine is the 3.0 ohm 12 volt version . I use the original model A distributor with original style points . Pertronix makes different coils for electronic ignition . Using the 40611 with electronic ignition could be a problem .
Purdy Swoft is offline   Reply With Quote
Old 02-11-2018, 04:31 PM   #25
Brian T
Senior Member
 
Brian T's Avatar
 
Join Date: May 2010
Location: San Diego,Ca
Posts: 1,247
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by 40 Deluxe View Post
Answer: It depends!......Depends on how much voltage is needed to jump the plug gap. If only 5,000 volts will fire the plug, that is all the coil will put out. Even if you have a double super whammy "40,000 volt" coil it will still only build up secondary voltage to the point where the spark is strong enough to jump the plug gap, which will never reach 40,000 volts on a Model A, or any stock engine (unless you have totally burned out plug electrodes or open wires, etc.). An ultra high compression or supercharged engine running at wide open throttle may need this much voltage capability, though.
To test coil output, try a "Lisle #20700 Spark Tester". Or, go to a shop with a scope, hook it up and pull a plug wire off and watch the screen.
Excellent post, this is the way I always remember it, using an oscilloscope can teach you much about the ignition system, spark plug cleaning machines had voltage testers built into them.
__________________
Nothing can be made foolproof, ---- fools are ingenious bastards.
Brian T is offline   Reply With Quote
Old 02-11-2018, 04:52 PM   #26
PRG999
Member
 
Join Date: Feb 2015
Posts: 41
Default Re: Replacement Ignition Coil

So can the 40611 Pertronix coil, epoxy filled be used on a stock 6 volt system?

Thanks
paul
PRG999 is offline   Reply With Quote
Old 02-11-2018, 05:15 PM   #27
jmeckel
Senior Member
 
jmeckel's Avatar
 
Join Date: Sep 2011
Location: Luck WI
Posts: 549
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by PRG999 View Post
So can the 40611 Pertronix coil, epoxy filled be used on a stock 6 volt system?

Thanks
paul
From their web site, for 6 volt systems use part number 40111 1.5 ohm epoxy.
__________________
Jon

"If you choose to not decide, you still have made a choice!" RUSH

Don't tell me what you know..... Tell me what you have done.
jmeckel is offline   Reply With Quote
Old 02-11-2018, 07:02 PM   #28
PRG999
Member
 
Join Date: Feb 2015
Posts: 41
Default Re: Replacement Ignition Coil

jmeckel

Thank you

Paul
PRG999 is offline   Reply With Quote
Old 02-11-2018, 07:15 PM   #29
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 26,981
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Bob Bidonde View Post
Tom,
After 90 years of service, what do you think the remaining life is? I hope you have a spare coil if you tour out of town in your Model A.
Sparks must be really small, because I'd have thought that size can would have emptied out years ago.
Tom Wesenberg is online now   Reply With Quote
Old 02-11-2018, 08:36 PM   #30
jb-ob
Senior Member
 
Join Date: Jun 2010
Posts: 146
Default Re: Replacement Ignition Coil

Tom's coil is authentic ..... "any color as long as it is black"
jb-ob is offline   Reply With Quote
Old 02-11-2018, 09:08 PM   #31
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Purdy Swoft View Post
If this was really the case, no matter what coil or distributor that was used would increase the spark . This is really no so !!! I use a gap of .035 - thats thirty five thousants at the spark plugs . Running at idle speed is not an extra strain on the coil . Idle speed doesn't require extra voltage to jump the .035 gap at the spark plugs. If my Flame thrower coil doesn't increase the spark . Why would the idle rpm increase to the point that I had to readjust the idle speed . I have had similiar results with other performance coils like the 30.000 volt bee hive coils . These coils give performance that a person that has actually used one can't deny .
The increase in idle speed was from opening the plug gap to .035". The increased gap allows for more fuel molecules to be available to be ignited by the spark, so idle speed increases (and emissions go down). In the '70's came stricter emissions laws. One way manufacturers met the standards was with leaner mixtures which required larger plug gaps to cut down on misfire. This required higher voltage coils and in turn better plug wires (most manufacturers went to 8mm wires). EPA also required cars to run longer without a tuneup so electronic ignition systems came into use. Ford went to about .050" gaps , most GM went to .045" gaps, and some Oldsmobiles used .080" for awhile.
Try setting two plugs in your A at .025" and two at .035" and hook it to a scope. Record the firing voltages. Then set the two plugs back to .035". You will see an increase in voltage on those two plugs. Next put on a stock A coil and see if the voltage changes from your 'hot' coil.
When the points open and voltage is induced in the secondary circuit, it only rises enough to jump the plug gap, no matter the coil's potential. With your A on the scope, pull the coil wire out of the distributor cap and watch the voltage rise on the scope as you hold the wire further away. In this case the 'hot' coil will produce a longer spark than the stock coil, because it has more voltage potential in reserve. In normal use, this higher potential is never reached.
40 Deluxe is offline   Reply With Quote
Old 02-12-2018, 12:17 AM   #32
gustafson
BANNED
 
Join Date: Oct 2017
Posts: 128
Default Re: Replacement Ignition Coil

40 Deluxe is correct
gustafson is offline   Reply With Quote
Old 02-12-2018, 01:07 PM   #33
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

I believe that Ford increased spark plug gap to .035 before model A production ended ... Anyway , I have always set my spark plug gap at .035 on my model A's and most others with points ignition . Spark plug gap had nothing to do with the rpm increase after installing a performance coil . The reason being that the gap had allways been at .035 , not readjusted to .035 after the installation of the flame thrower coil .I agree that more spark plug gap , to a point better burns the fuel . I agree that spark plug gap increased with the introduction of electronic ignition . The coils would have had to have been improved to handle wider spark plug gaps . Standard , ( not necessarily brand) , replacement coils for points ignition will fail rather quickly If the gap is opened too wide ! I have used other performance coils and they all increased idle rpm and noticably improvement performance . This is my experience .
Purdy Swoft is offline   Reply With Quote
Old 02-12-2018, 01:19 PM   #34
gustafson
BANNED
 
Join Date: Oct 2017
Posts: 128
Default Re: Replacement Ignition Coil

your claim about better performance would not be measured by most by a change of rpm at idle, which isn't much of a yardstick.
Are there any dyno data to support this claim. What is happening at speed is the real measure.
Somehow 10K volt coils got us thru the first 80 years of the Model A, and suddenly they are inadequate?
gustafson is offline   Reply With Quote
Old 02-12-2018, 01:49 PM   #35
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

I figured that would be the next negitive comment . As I have said many times before , I have nothing to prove or gain here. Actually I never said that idle rpm was the test of increased power. Performance coils obviously are not for everyone . You could probably find a coil that would fill your needs , if you need one . at NAPA.
Purdy Swoft is offline   Reply With Quote
Old 02-12-2018, 06:34 PM   #36
gustafson
BANNED
 
Join Date: Oct 2017
Posts: 128
Default Re: Replacement Ignition Coil

already did, car runs fine
gustafson is offline   Reply With Quote
Old 02-12-2018, 09:23 PM   #37
2manycars
Senior Member
 
2manycars's Avatar
 
Join Date: May 2010
Location: Eastern CT
Posts: 2,689
Default Re: Replacement Ignition Coil

My tudor has the coil that was on the car when I bought it 43 years ago. It runs fine.
__________________
Bill
www.brauchauto.com
2manycars is offline   Reply With Quote
Old 02-12-2018, 10:46 PM   #38
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

None of the model A's that I have now even had a coil when I got them .
Purdy Swoft is offline   Reply With Quote
Old 02-13-2018, 02:44 AM   #39
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Purdy Swoft View Post
I believe that Ford increased spark plug gap to .035 before model A production ended ... Anyway , I have always set my spark plug gap at .035 on my model A's and most others with points ignition . Spark plug gap had nothing to do with the rpm increase after installing a performance coil . The reason being that the gap had allways been at .035 , not readjusted to .035 after the installation of the flame thrower coil .I agree that more spark plug gap , to a point better burns the fuel . I agree that spark plug gap increased with the introduction of electronic ignition . The coils would have had to have been improved to handle wider spark plug gaps . Standard , ( not necessarily brand) , replacement coils for points ignition will fail rather quickly If the gap is opened too wide ! I have used other performance coils and they all increased idle rpm and noticably improvement performance . This is my experience .
Now you've got my curiosity up! How much was the increase in idle RPM? I need to do some experimenting to see if I can duplicate your results.
40 Deluxe is offline   Reply With Quote
Old 02-13-2018, 10:45 AM   #40
gustafson
BANNED
 
Join Date: Oct 2017
Posts: 128
Default Re: Replacement Ignition Coil

40 Deluxe, help me to understand what that would have to do with performance at speed, which is where the real money is

anyone got a dyno handy?

I suspect that somehow the timing was changed slightly
gustafson is offline   Reply With Quote
Old 02-13-2018, 11:16 AM   #41
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by gustafson View Post
40 Deluxe, help me to understand what that would have to do with performance at speed, which is where the real money is

anyone got a dyno handy?

I suspect that somehow the timing was changed slightly
Gustafson, I don't have a dyno so can only do the idle test. I agree with you on the timing change possibility. That, or the original coil (or condenser) was weak.
40 Deluxe is offline   Reply With Quote
Old 02-13-2018, 11:40 AM   #42
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

Nobody said that idle speed had anything to do with all out performance , its just a characteristic of the performance coils that I have used . You obviously have problems with reading comprehension . . .
Purdy Swoft is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-13-2018, 12:05 PM   #43
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Purdy Swoft View Post
Nobody said that idle speed had anything to do with all out performance , its just a characteristic of the performance coils that I have used . You obviously have problems with reading comprehension . . .
No, just trying to comprehend why a coil with higher voltage potential would increase idle speed when that higher potential is not being used; when both an original coil and a performance coil are providing the same voltage at idle.
At full throttle I can see an original coil not providing consistent spark, but the voltage demand is much higher than at idle. So I'm going to do the idle test and try to prove myself wrong.
40 Deluxe is offline   Reply With Quote
Old 02-13-2018, 01:07 PM   #44
gustafson
BANNED
 
Join Date: Oct 2017
Posts: 128
Default Re: Replacement Ignition Coil

40 Deluxe, suppose a brand new coil fires a split second sooner when the points open, that would be the same as more advance. And something that would be both hard to measure and the resulting increase in RPM of no meaning; would love to know your test results
Mr Swoft how many would be concerned about compression blowing out a spark with a 4.2 head at 2200 rpm. A 10:1 head at 7K, that would be different .
Spark, timing, coils, points and such can be confusing and could be a great thread to clarify from. To many, timing and ignition and spark is just shoving a pin in a hole

Last edited by gustafson; 02-13-2018 at 01:45 PM.
gustafson is offline   Reply With Quote
Old 02-13-2018, 02:21 PM   #45
duke36
Senior Member
 
Join Date: Jun 2015
Posts: 835
Default Re: Replacement Ignition Coil

See the attached article though not sure how much science data is involved.. Perhaps it will help with Bob's initial ?. Note the sentence that the 2ndary output is around 100 x the primary voltage with other parameters in force as well.
Removed the attached, may be corrupted file. Go to MGAguru.com "Ignition Coil and Testing" and see if it opens.

Last edited by duke36; 02-14-2018 at 07:05 PM.
duke36 is offline   Reply With Quote
Old 02-13-2018, 02:24 PM   #46
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 6,531
Default Re: Replacement Ignition Coil

Why not ask Pertronix ??? Maybe they can clear up your confusion ... This is the last time that I will open this thread .
Purdy Swoft is offline   Reply With Quote
Old 02-13-2018, 03:07 PM   #47
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by duke36 View Post
See the attached article though not sure how much science data is involved.. Perhaps it will help with Bob's initial ?. Note the sentence that the 2ndary output is around 100 x the primary voltage with other parameters in force as well.
One point not addressed in that article is the great variation in secondary voltage output. As the primary field collapses and induces secondary voltage, secondary voltage only rises to the amount needed to jump the plug gap. If 5,000 volts will fire the plug, that is what the coil produces, no more. If it takes 10,000 volts to jump the plug gap, that is what the coil produces. During my career as a mechanic, I've had many vehicles hooked to a scope and seen this. A fouled plug or a plug wire shorted to ground shows a very low coil output. An open plug wire or worn plugs with large gaps show higher output voltages. We also did a 'snap test', snapping the throttle wide open quickly. This also raised the voltage requirement significantly. If one cylinder showed an abnormal spike, it was the problem child.
40 Deluxe is offline   Reply With Quote
Old 02-13-2018, 03:12 PM   #48
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by gustafson View Post
40 Deluxe, suppose a brand new coil fires a split second sooner when the points open, that would be the same as more advance. And something that would be both hard to measure and the resulting increase in RPM of no meaning; would love to know your test results
Mr Swoft how many would be concerned about compression blowing out a spark with a 4.2 head at 2200 rpm. A 10:1 head at 7K, that would be different .
Spark, timing, coils, points and such can be confusing and could be a great thread to clarify from. To many, timing and ignition and spark is just shoving a pin in a hole
Well, I don't see how a new coil would fire any sooner. Electrical current would travel at the same speed in either coil. If anything, a performance coil likely has more turns of wire around the core, so current would take longer to complete the circuit but this would be insignificant, even meaningless.
40 Deluxe is offline   Reply With Quote
Old 02-13-2018, 04:40 PM   #49
mshmodela
Senior Member
 
mshmodela's Avatar
 
Join Date: Mar 2014
Location: Cleveland, Ohio
Posts: 2,748
Default Re: Replacement Ignition Coil

LOL TOM! I have yet to install my flamethrower coil.I lost all spark 2 year ago and after the car cooled down she fire up.. It's not done it since.
__________________
-Mike

Late 31' Ford Model A Tudor, Miss Daisy

I don't work on cars --I'm learning about my Model A.

Cleveland, Ohio
mshmodela is offline   Reply With Quote
Old 02-13-2018, 10:25 PM   #50
40 Deluxe
Senior Member
 
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 2,412
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by gustafson View Post
40 Deluxe, suppose a brand new coil fires a split second sooner when the points open, that would be the same as more advance. And something that would be both hard to measure and the resulting increase in RPM of no meaning; would love to know your test results
Mr Swoft how many would be concerned about compression blowing out a spark with a 4.2 head at 2200 rpm. A 10:1 head at 7K, that would be different .
Spark, timing, coils, points and such can be confusing and could be a great thread to clarify from. To many, timing and ignition and spark is just shoving a pin in a hole
OK, did my idle test this afternoon. I did it on my '40 Ford, all stock with the exception of a remote coil adapter on the original helmet distributor. The coil is a 6 volt 1.5 ohm Echlin of unknown vintage, but old. The engine idled at 610-615 RPM. I then mounted a new out of the box 12 V. Bosch 012 coil and powered it with jumpers directly from a 12 V. battery. The engine idled at 595-600 RPM. Reconnected the first coil and idle RPM went to about 605 RPM. Revving in neutral, both coils sounded the same.
So no RPM increase for me.
40 Deluxe is offline   Reply With Quote
Old 02-14-2018, 10:55 AM   #51
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 1,401
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by duke36 View Post
See the attached article though not sure how much science data is involved.. Perhaps it will help with Bob's initial ?. Note the sentence that the 2ndary output is around 100 x the primary voltage with other parameters in force as well.
File Type: pdf Ignition coil function and testing.pdf (169.7 KB, 19 views)

Comes up blank
__________________
Talk slow, think fast.

Last edited by katy; 02-14-2018 at 10:55 AM. Reason: Correction
katy is offline   Reply With Quote
Old 02-14-2018, 07:07 PM   #52
duke36
Senior Member
 
Join Date: Jun 2015
Posts: 835
Default Re: Replacement Ignition Coil

see post 45 for article web location.
duke36 is offline   Reply With Quote
Old 02-14-2018, 10:41 PM   #53
pgerhardt
Senior Member
 
pgerhardt's Avatar
 
Join Date: Jul 2014
Location: Danbury Ct
Posts: 1,225
Default Re: Replacement Ignition Coil

Quote:
Originally Posted by Tom Wesenberg View Post
I'm not sure if my original coil is reliable, as I'm still testing it. It's only been in use for 90 years.
The picture looks like a slant pole coil. I got one (at Hershy) for my 29 tudor because it was correct for that year. My tudor practically sighed with delight when I installed it. It started better and ran better. Glad I am set for the next 90 years!
pgerhardt is offline   Reply With Quote
Old 02-15-2018, 10:33 AM   #54
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 1,401
Default Re: Replacement Ignition Coil

duke36, thanks, I found it.

I've been testing a bunch of old 6 volt coils and also some 12 volt ones that call for a ballast resistor, but not using one and testing them using 6 volts.
They all put out around 25KV, some as high as 28 KV.
For testing I use an old GM distributor clamped in a vise and turn the shaft by hand to open and close the points.

I've been using a tester similar to this one:
Attached Images
File Type: jpg Spark strength tester.jpg (58.1 KB, 13 views)
__________________
Talk slow, think fast.
katy is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 07:13 AM.